1. Field of the Invention
The present invention relates to a heat exchanger having multiple heat exchanger units that are integrally formed.
2. Description of Related Art
Conventionally, JP-A-2002-115991 (corresponding to US2002/0040776) discloses a heat exchanger, which has multiple tubes allowing fluid to flow therethrough, and which has a header tank provided at longitudinal end portions of the tubes to be communicated with the tubes. Multiple heat exchanger units are integrally formed by partitioning an internal space of the header tank by partition walls (separators).
In the heat exchanger of JP-A-2002-115991, the header tank includes a core plate and a tank main body. The core plate has tube insertion bores, into which the tubes are inserted in a bonded manner. The tank main body, together with the core, plate, defines an in-tank space. Also, a gasket is provided at a position between the adjacent tube insertion bores of the core plate, and when the partition wall compresses the gasket, the gap between the partition wall and the core plate is sealed.
Also, JP-A-2003-336994 discloses a heat exchanger, in which a gap between the partition wall and the core plate is sealed by forming two plate members along a length of the end portion of the partition wall at the end portion of the partition wall adjacent the core plate, without providing a gasket.
Also, in the heat exchanger of JP-A-2002-115991, a position between tube insertion bores that are located adjacent the core plate serves as a seal surface, and the part is processed to have a burring for receiving a tube. Thus, the part between the tube insertion bores has a curved shape. Originally, in order to secure sealing performance for sealing between the partition wall and the core plate, it is required to apply a compression force perpendicular to the gasket uniformly. However, because the seal surface has the curved shape, it is difficult to apply the uniform compression force to the entirety of the seal surface, and thereby it is difficult to sufficiently secure the sealing performance.
Also, in the heat exchanger of JP-A-2003-336994, because the gasket is eliminated, it is disadvantageously impossible to sufficiently secure the sealing performance.